Just bought the 106S/2 last night from newegg. Can't wait to get it. I couldn't figure out the difference either ... checked Pioneer's website and they don't have the 106S/2 listed at all. Wanted to konw the differences myself. All the read features (speed, cache) are the same between the two, the only difference is in the picture.
edit - This was post #500 for me
I've had the 106S (not the /2 version) for about a year. No problems at all. Have it's older brother, the 104S on an older machine, about 2 1/3 years wear-and-tear, no problems there either.
Can't comment on any difference between 106S and 106S/2... sorry.